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· One min read
Jean-Philippe Raynaud

High level overview​

The Mithril team continued working on decentralizing the signature orchestration of the Mithril network. They kept implementing a buffer store for individual signatures that may arrive before being processed by an aggregator, worked on refactoring the signer state machine, and started developing a mechanism to support specific configurations for signing Cardano transactions. Additionally, they fixed the panics occurring in the signer and aggregator during Cardano chain rollbacks.

Finally, the team continued preparing the next distribution and investigated a problem preventing the consistent certification of Cardano transactions in the pre-release-preview network.

Low level overview​

  • Completed the issue Panic on rollback on slot number not recorded in the Cardano transactions store #1929
  • Completed the issue Test Cardano transaction chain rollbacks #1840
  • Worked on the issue Release 2437 distribution #1901
  • Worked on the issue Cardano transactions certification stopped in pre-release-preview #1938
  • Worked on the issue Aggregator buffers signatures for unknown open message #1900
  • Worked on the issue Refactor state machine of the signer #1922
  • Worked on the issue Retrieve custom signing configurations with epoch settings in signer #1923
  • Worked on the issue Breaking change in crane fails Hydra CI #1928

· 2 min read
Marcin Szamotulski

High-level overview of sprint 70​

Cardano CLI​

cardano-cli ping command cannot send pings over unix sockets using node-to-client mini-protocol (since it doesn't support it). In that case, the command will now show a user-friendly error message. See cardano-cli#49.

Mithril​

We held a session with the mithril team to discuss design & implementation of Mithril using ouroboros-network.

Ouroboros-Network​

TxSubmission Logic​

We continued working on tx-submission logic. We developed new tests that run several simulated outbound peers offering transactions and a single inbound peer governed by the new tx-submission logic. Ref ouroboros-network#3311.

The next step is to clean the branch and integrate it with ouroboros-consensensus & cardano-node for early e2e tests.

Bulk-Sync for Genesis​

We reviewed the new bulk-sync application for Genesis mode, see ouroboros-network#4919.

Typed-Protocols​

We reviewed the new typed-protocols API PR. It was recently merged & published to CHaP. Once Haskell.Nix has better support for public sub-libraries, we will package all the libraries in one package and publish it on Hackage. Ref: typed-protocols#52.

The next step is to update, review the integration PR in ouroboros-network, see ouroboros-network#4935.

Nightly Tests​

We fixed a long-due failure on a nightly test. The failure was due to IOSimPOR ability to reorder simulated IO actions, resulting in a wrong order of events. So, it's not a bug in the production code but in the test itself. See ouroboros-network#4948.

Updated readme file​

We updated the dependency graph in our README.md file.

Next Sprint​

sprint-71

· 2 min read
Jordan Millar

2024-09-04 - 2024-09-18

High level summary​

In line with our ongoing refactoring work, we began propagating the experimental api in cardano-cli. This will continue for several sprints as we remove eras prior to mainnet in order to reduce the unnecessary complexity of cardano-api's and cardano-cli's codebases. Other work:

  • New functionality has been added to cardano-cli and cardano-ping
  • Collateral balancing bug has been fixed in cardano-cli
  • optparse-applicative-fork dependency has been removed
  • Various refactors and improvements to cardano-testnet

cardano-cli​

cardano-api​

cardano-node​

cardano-testnet​

docs​

CI & project maintenance​

· One min read
Kevin Hammond

Unexpected Ledger State Replay in the Conway era​

An issue was identified shortly before the Chang hard fork: it was found that ledger state snapshots would break ledger replay in the Conway era under mainnet conditions. The ledger and consensus teams worked rapidly to resolve the issue with a hotfix released within 24 hours of the hard fork. In order to avoid pauses in node availability, it was recommended that users should not restart their node process until they had upgraded their node to the hotfix - this included any node type: relays, block producers, DB-Sync nodes, etc.

The issue is documented here. The cause was a slight inconsistency between the ledger state snapshots that were written and those that could be read back; a side effect of the removal of pointer addresses in the Conway era. Nodes version 9.1.1 and later resolve this issue.

Further Details​

Node version 9.1.1

GitHub Issue

· 2 min read
Kevin Hammond

Issue Caused by Large Reference Scripts on Cardano Mainnet​

On 25th June 2025, a Cardano user inserted a series of transactions, each containing 194 large reference scripts onto the mainnet chain, funded from 3 wallets containing around 20K ada each. High deserialisation costs for these reference scripts impacted the node, resulting in network disruption to block producer nodes, an increase in network load, and some slowdown in transaction throughput.

The direct effect lasted about 12 hours until it was stopped by a community member, at a cost of 4603 ada to the user who had created the transactions. Overall, the network responded extemely well to the increased load, showing a high level of resilience, with some reduction in transaction throughput related to the overall high system load. The community response to the event was positive, praising the speed of response, the robustness of the Cardano network, the cohesion of the Cardano community, and its ability to diagnose and manage issues such as this.

Mitigations Deployed​

The general issue had already been identified, and a mitigation (costing for reference scripts) had been prepared as part of the Chang hard fork, but not yet deployed to mainnet. Based on the event, stronger mitigations were prepared, including restricting large reference scripts, and changing the cost model. These mitigations were deployed via node versions 8.9.4, 8.12.1 or 8.12.2, and incorporated into node version 9.0.0 or later for the Chang hard fork.

Public Reports on the Incident​

Coindesk Report

Nasdaq Report